单项选择题
I（）finish my homework now. I can do it at the weekend.
A.have to B.don‘t have to C.must D.mustn‘t
单项选择题 People wandering in the fairground or park area（）wear a uniform.
单项选择题 Not until most of the people had left the airport（）his sister was there.
单项选择题 Not always（）they want (to)
